1. Technical Field
The present invention relates to a technique for detecting a mark provided to a web.
2. Related Art
Japanese laid-open patent publication No. 2006-76169 discloses a print apparatus with which a mark formed on a surface of a web is detected by a detecting means. In particular, a configuration for detecting fouling or abnormality in the detecting means in advance is provided, in order to address a problem where a mark is erroneously detected due to fouling or abnormality in the detecting means.
However, the erroneous detection of a mark can also take place due to causes other than fouling, abnormality, or the like of a detector (detecting means). In one example, when foreign matter adheres to the web, then the foreign matter passes through the front of the detector and alters an output signal of the detector. As a result, there is the risk that this foreign matter could be erroneously detected as a mark. Alternatively, in a case where the web is stopped in a state where a mark is located in the vicinity of the detector, then when the web vibrates due to being pushed by a gusting air flow or the like, the mark sways in front of the detector and alters the output signal of the detector. As a result, there is the risk that the mark could end up being erroneously detected.